Pages intended to be reused as portions of other pages are called templates. The names of template pages start with the prefix Template:. A template can be included on another page using the syntax {{Page name}}, but do not include the prefix between the curly brackets!.
On Wikipedia, templates are created to serve a variety of purposes, such as navigation boxes (e.g. Template:Europe), infoboxes, and notices (e.g. Template:Controversial).
Read more: Wikipedia:Template